Adapter for attaching electromagnetic image guidance components to a medical device

ABSTRACT

Devices and methods wherein an adapter is used to attach an electromagnetic image guidance component to a medical device such that an electromagnetic image guidance system may be used to track the location of the medical device within the body of a human or animal subject.

FIELD OF THE INVENTION

The present invention relates generally to medical devices, systems andmethods and more particularly to methods and apparatus for attachingelectromagnetic image guidance components to guide catheters and othermedical devices that are useable in performing therapeutic or diagnosticprocedures.

BACKGROUND OF THE INVENTION

Image guided surgery (IGS) procedures (sometimes referred to as“computer assisted surgery”) were first developed for use inneurosurgery and have now been adapted for use in certain ENT surgeries,including sinus surgeries. See, Kingdom T. T., Orlandi R. R.,Image-Guided Surgery of the Sinuses: Current Technology andApplications, Otolaryngol. Clin. North Am. 37(2):381-400 (April 2004).Generally speaking, in a typical IGS procedure, a digital tomographicscan (e.g., a CT or MRI scan) of the operative field (e.g., the nasalcavities and paranasal sinuses) is obtained prior to surgery. Aspecially programmed computer is then used to convert the digitaltomographic scan data into a digital map. During surgery, sensors ormarkers mounted on the surgical instruments send data to the computerindicating the position of each surgical instrument. The computercorrelates the data received from the instrument-mounted sensors withthe digital map that was created from the preoperative tomographic scan.One or more image(s) is/are then displayed on a monitor showing thetomographic scan along with an indicator (e.g., cross hairs or anilluminated dot) of the real time position of the surgical instrument.In this manner, the surgeon is able to view the precise position of eachsensor-equipped instrument relative to the surrounding anatomicalstructures shown on the tomographic scan.

The currently available IGS systems fall into two main categories,namely, optical systems and electromagnetic systems. In electromagneticIGS systems, electromagnetic sensors (e.g., electromagnetic coils) areattached to the surgical instrument and the computer determines theposition of the instrument within the body on the basis of signalsreceived from those electromagnetic sensors. Examples of commerciallyavailable electromagnetic IGS systems that have been used in ENT andsinus surgery include the ENTrak PIus™ and InstaTrak ENT™ systemsavailable from GE Medical Systems, Salt Lake City, Utah. Other examplesof electromagnetic image guidance systems that may be modified for usein accordance with the present invention include but are not limited tothose available from Surgical Navigation Technologies, Inc., Louiville,Colo., Biosense-Webster, Inc., Diamond Bar, Calif. and Calypso MedicalTechnologies, Inc., Seattle, Wash.

The electromagnetic sensors must be attached to the instrument in amanner that maintains the sensors in specific, fixed spatialrelationships to the portion of the instrument that is to be trackedwithin the body. In some cases, the sensor(s) may be built into theinstruments at the time of manufacture. In other instances, it may bedesirable to attach one or more electromagnetic sensors (or a modulecontaining the sensor(s)) to an instrument immediately prior to orduring use of that instrument in a therapeutic procedure.

In the ENT field, one particular area in which it is desirable to attachelectromagnetic sensors to instruments is in the performance ofprocedures where rigid and/or flexible catheters and other devices areinserted through the nose and used to perform sinus surgery or othersinus treatment procedures. One such procedure is balloon dilation ofsinus cavity ostia. In such procedure, a guide catheter having asubstantially fixed shape is inserted through the nose and advanced to aposition where the distal end of the guide catheter is adjacent to theostium of a paranasal sinus. A guidewire is then advanced through theguide catheter (e.g., Relieva™ Guide Catheter, Acclarent, Inc., MenloPark, Calif.) and into the paranasal sinus. Thereafter, a ballooncatheter (e.g., Relieva™ Balloon Catheter, Acclarent, Inc., Menlo Park,Calif.) is advanced over the guidewire and is used to dilate the ostiumof the paranasal sinus, thereby improving drainage from and/orventilation of that paranasal sinus. Since the guide catheter has asubstantially fixed shape, electromagnetic sensors may be mounted on theproximal portion of the guide catheter in positions that bear knownspatial relation to the distal end of the guide catheter. In thismanner, those proximally mounted sensors may be used in conjunction withan electromagnetic IGS system to track the position of the distal end ofthe guide catheter within the subject's body. However, to accomplishthis, the sensors must be firmly mounted and maintained in specificpositions on the proximal end of the guide catheter.

Thus, there remains a need in the art for the development of new adapterdevices that may be used to securely attach electromagnetic sensors (orreceiver modules that contain the sensor(s)) to guide catheters and/orother devices useable in the performance of balloon dilation proceduresas well as other instruments used in ENT and other surgical procedures.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided an adapter deviceuseable for attaching an electromagnetic image guidance element (theelectromagnetic image guidance element can be either a receiver or atransmitter) to a medical device, such as a guide catheter or otherdevice, for example a guide catheter having a balloon, having a distalportion that becomes inserted into the body of a human or animal subjectand a proximal portion that remains outside of the subject's body. Thisadapter device generally comprises (a) a medical device holding fixtureconstructed to be firmly attached to the proximal portion of the medicaldevice and (b) a element holding fixture constructed to firmly hold theimage guidance element in substantially fixed spatial relation to atleast one location on the distal portion of the medical device whileallowing the distal portion of the medical device to be inserted intothe subject's body for purposes of the procedure with a high degree ofaccuracy.

Further in accordance with the invention, there is provided a method forperforming an image guided therapeutic or diagnostic procedure withinthe body of a human or animal subject. In general this method includesthe steps of (a) providing a medical device having a distal portion thatis inserted into the subject's body and a proximal portion that remainsoutside of the subject's body, said medical device being useable toperform or facilitate the performance of at least part of the procedure,(b) providing an IGS system that includes a element which communicatessignals to a computing device which uses said signals to determine thelocation of a device within the body of a human or animal subject, (c)providing an adapter device that includes i) a medical device holdingfixture constructed to be firmly attached to the proximal portion of themedical device and ii) a element holding fixture constructed to firmlyhold the image guidance element in substantially fixed spatial relationto the distal portion of the medical device while allowing the distalportion of the medical device to be inserted into the subject's body andallowing the medical device to be used to perform or facilitate theperformance of at least part of the procedure, (d) attaching theproximal portion of the medical device to the adapter device by way ofthe medical device holding fixture, (e) attaching the element to theadapter device by way of the element holding fixture, (f) inserting thedistal end of the medical device into the subject's body, (g) using theIGS system to guide the positioning of at least one location on thedistal portion of the medical device within the subject's body and (h)using the medical device to perform or facilitate the performance of atleast part of the procedure. In some embodiments, the IGS system can beused in conjunction with an endoscope and/or a fluoroscope system. Insome embodiments of the invention, the medical device may be a guidewireor guide catheter that has a substantially fixed shape and Step H of themethod may be carried out by advancing another device over the guidewireor through the guide catheter.

Still further in accordance with the invention there is provided acalibration tool for use in calibrating an IGS system to an elongatemedical device that has a substantially fixed shape and a distal end. Ingeneral, such calibration tool comprises a substantially rigid bodyhaving a receiving groove, a first calibration tip and may include asecond calibration tip. In a preferred embodiment, first and secondcalibration tips extend in 180 degree opposite directions from oneanother. The elongate medical device (e.g., a curved guide catheter) isinsertable into the receiving groove with its distal end positioned in aknown position relative to the first and second calibration tips. Thefirst and second calibration tips are alternately placeable in a knownlocation relative to an electromagnetic transmitter such that readingsmay be taken by the IGS system and used to calibrate the IGS system tothe shape of that medical device.

Still further in accordance with the invention there is provided amethod for calibrating an image guided surgery system for use with anelongate medical device that has a substantially fixed shape and adistal end. In general, this method comprises the steps of (a) providinga calibration tool comprising a substantially rigid body having areceiving groove, a first calibration tip and a second calibration tipformed therein, said first and second calibration tips extending is 180degree opposite directions from one another, (b) inserting the medicaldevice into the receiving groove with the distal end of the medicaldevice positioned in a known position within one of said first andsecond calibration tips, (c) positioning the first calibration tip in aknown position relative to an electromagnetic transmitter whileobtaining at least one reading using the image guided surgery system,(d) positioning the second calibration tip in a known position inrelation to the electromagnetic transmitter while obtaining at least oneadditional reading using the image guided surgery system and (e)calibrating the image guided surgery system to the substantially fixedshape of the medical device on the basis of the readings obtained inSteps C and D. In some embodiments, multiple readings may be taken inSteps C and D wile maintaining the first and second calibration tips inthe known position relative to the electromagnetic transmitter. In someinstances, a receiving location (e.g., a well, notch, cavity or otherdepression) may be formed in the electromagnetic transmitter and thecalibrations tips may be maintained in the known location relative tothe transmitter by inserting those calibration tips into the receivinglocation.

Further aspects, details and embodiments of the present invention willbe understood by those of skill in the art upon reading the followingdetailed description of the invention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear perspective view of a system wherein a first embodimentof an adapter device of the present invention is used to attach anelectromagnetic image navigation element to a guide catheter.

FIG. 2 is an exploded view of components which make up the adapterdevice shown in FIG. 1.

FIG. 3 is a bottom view of the adapter device shown in FIG. 1.

FIG. 4A is a front view of a calibration tool of the present invention.

FIG. 4B is a rear view of the calibration tool of FIG. 4A.

FIG. 4C is a front view of the calibration tool of FIG. 4A in use duringa calibration procedure according to the present invention.

FIG. 5A is a front perspective view of another embodiment of an adapterdevice of the present invention useable for attaching an electromagneticimage navigation element to a guide catheter.

FIG. 5B is a side view of the adapter device of FIG. 5A having a guidecatheter attached thereto.

FIGS. 5C and 5D show steps in a method for attaching the guide catheterto the adapter device of FIG. 5A.

DETAILED DESCRIPTION

The following detailed description and the accompanying drawings areintended to describe some, but not necessarily all, examples orembodiments of the invention. The contents of this detailed descriptionand the accompanying drawings do not in any way limit the scope of theinvention disclosed herein.

FIGS. 1-3 show an adapter device 10 of the present invention that isdesigned to facilitate attachment of an electromagnetic image guidanceelement 12 to a medical device which, in this example, comprises a guidecatheter 14. In another embodiment, the medical device can be a stiffmember with a dilatation balloon on the distal end. The stiff member canbe hollow to allow passage of other medical devices therethrough or toallow suction and/or irrigation therethrough. The guide catheter 14comprises a tubular shaft 16 having a lumen, an optional curve 18 and anopen distal end DE. A Luer hub 15 which may optionallly include radiallyopposing projections 40 is mounted or formed on the proximal end PE ofthe guide catheter 14. The guide catheter shaft 16 is of substantiallyfixed size and shape such that the spatial relationship of the distalend DE to the proximal end PE is known. The image guidance element 12contains electromagnetic sensors that provide signals useable by an IGSsystem. In typical useage, a distal portion DP of the guide catheter 14becomes inserted into the subject's body while a proximal portion PPremains outside of the subject's body. The adapter device 10 firmlyholds the guide catheter 14 and element 12 such that the electromagneticsensors located in the element are in substantially fixed spatialrelation to the distal end DE of the guide catheter 10. As explainedmore fully herebelow, this enables the IGS system to track the locationof the distal end DE of the guide catheter 10 within the body of a humanor animal subject.

One example of a commercially available embodiment of the guide catheter10 is the Relieva™ Sinus Guide Catheter available from Acclarent, Inc.of Menlo Park, Calif. One example of a commercially available embodimentof an IGS element 12 useable in this invention is the InstaTrak®Receiver available from GE Healthcare, Inc. of Schenectady, N.Y.

With reference to the showings of FIGS. 1-3, one embodiment of theadapter 10 comprises an adapter body 20 having a element holding fixture22 and a guide catheter holding fixture 24. In this example, the elementholding fixture 22 comprises first and second clamping members 26 whichare useable to clamp and hold the element 12 in fixed position on theunderside of the adapter device body 20, as shown. Also, in thisexample, the guide catheter holding fixture 24 comprises a guidecatheter receiving channel 28 which comprises first guide catheterfixture member 28 a and a second guide catheter fixture member 28 b. Asexplained in more detail herebelow, a tightening mechanism 30 whichtightens the guide catheter receiving channel 28 about the proximalportion PP of the guide catheter shaft 16, thereby firmly holding theguide catheter 14 in place. In order to facilitate ease of use of thesystem including creating less interference with an endoscope used bythe physician and a comfortable angle for the phyisician's handpreferably the guide catheter receiving channel is at an angle between 0and 45 degrees relative to the element holding fixture, and mostpreferably at an angle of 20 degrees.

The exploded view of FIG. 2 shows specific components of which thisembodiment of the adapter device 10 is assembled. It is to beappreciated that this is merely an example, and various othercomponents/modes of construction may be employed as alternatives to thatseen in these figures. As shown, this embodiment of the adapter device10 comprises an upper body portion 20 a that is attached to a lower bodyportion 20 b. Element clamping members 26 a, 26 b are attached to thelower body portion 20 b. A first guide catheter fixture member 28 a isformed integrally of the upper body portion 20 a and a second guidecatheter fixture member 28 b is pivotally attached to the upper bodyportion 20 a by way of a hinge which pivots about a pin 30. A screw 32having a screw head 36 thereon is received within threaded bore 34.Turning of the screw head 36 in a first direction causes the secondguide catheter fixture member 28 b to pivot toward the second guidecatheter fixture member 28 a, thereby tightening the guide catheterreceiving channel 28 so as to firmly grasp the guide catheter shaft 16.Turning of the screw head 36 in a second direction causes the secondguide catheter fixture member 28 b to pivot away from the second guidecatheter fixture member 28 a, thereby widening the guide catheterreceiving channel 28 so as to allow the guide catheter shaft 16 to beinserted into or removed from the guide catheter holding fixture 24 orto allow adjustment of the longitudinal position or rotationalorientation of the guide catheter 14 relative to the adapter device 10.

The components of the adapter device 20 may be formed of any suitablematerials. In some embodiments, the components of the adapter body 20may be molded from acrylonitrile butadiene styrene (ABS) or otherpolymeric material having suitable properties. In other embodiments, thecomponents of the adapter body 20 can be metal so as to beresterilizable.

The upper body portion 20 a may be attached to the lower body portion 20b in a number of ways including mechanical or frictional connections or,as shown in the example of FIG. 2, by way of adhesive pads 38 usingsuitable adhesive. In embodiments where the upper and lower bodyportions 20 a, 20 b are formed of ABS, a suitable adhesive would beepoxy or cyanoacrylate.

In one embodiment of a method for attaching the guide catheter 14 to theadapter device 10, the screw head 36 is initially turned in acounter-clockwise direction to widen the guide catheter receivingchannel 28 to a width wider than the outer diameter of the guidecatheter shaft 16. The guide catheter shaft 16 is then inserted throughthe channel 28 and positioned such that the proximal portion PP if theguide catheter shaft 16 is within the channel 28 and the guide catheter14 is in the desired rotational orientation. Thereafter, the screw head36 is turned in the clockwise direction, causing the channel 28 tonarrow until sufficient clamping force is exerted on the guide cathetershaft 16 to hold the guide catheter 14 in substantially fixedlongitudinal position and to substantially prevent subsequent rotationalmovement of the guide catheter shaft 16 relative to the adapter device10. Optionally, in embodiments where opposing radial projections 40 areformed on the Luer hub 15 or elsewhere on the proximal portion PP of theguide catheter 14, corresponding receiving notches 42 may be formedwithin the guide catheter receiving channel 28, as shown in FIG. 2. Theopposing radial projections 40 with be firmly held within notches 42thereby defining and maintaining the rotational orientation of the guidecatheter 14 relative to the adapter device 10. The clamping force of thepresent invention on the shaft 16 and/or the Luer hub 15 is important toeliminate relative motion between the guide catheter and adapter device10 and correspondingly the element 12 resulting in very good accuracy inidentifying the location of the distal tip of the guide catheter in thepatient using the IGS system. In embodiments where the guide cathetershaft 16 includes a curve, the opposing radial projections 40 may extendon a transverse axis TA that is parallel to the direction in which thecatheter shaft 16 curves, referred to herein as the “curve direction”CD. In illustration of this concept, in the embodiment of FIG. 1, thecatheter shaft 16 has a 90 curve which extends in a particular curvedirection CD that is parallel to the transverse axis TA of the opposingradial projections 40. The notches 42 are formed at 12 o'clock and 6o'clock positions within the guide catheter receiving channel 28. Thus,when the opposing radial projections 40 are held within notches 42 asdescribed, the curve direction CD will be straight up (or straight down)and in this manner the surgeon and the IGS system will at all times beapprised of the rotational orientation of the guide catheter 14.

FIG. 3 shows the underside of the adapter body 20. Indicia indicatingspecific information on the adapter device 10 (e.g., the size and typeof medical device that is to be attached, etc.) may be formed on theunderside of the adapter body 20 such that when the element 12 ispositioned in the element holding fixture 24, it will recognize or readthe indicia provided, and the IGS system may be programmed to makeadjustments (e.g., software or computational adjustments) in response tosuch indicia. In this example, such indicia are in the form of uniquemagnetic field(s). To create such magnetic field(s), one or more of themagnet receiving slots 42 hold identifying magnet(s) 44 in a manner thatcreates the desired unique magnetic field(s). The unique identifyingmagnetic field is sensed by the electromagnetic navigation element 12and communicated to the IGS system which is programmed to determine, onthe basis of such information, the particular type of guide catheter 14(or other medical device) that is (or will be) attached to the adapterdevice 10. For example, three identifying magnets 42 fixed to thesecond, third and fourth magnet slots 42 as shown in FIG. 2 may indicatethat the particular curved guide catheter 14 shown in FIG. 1 is attached(or will be attached) to the adapter device 10.

The position and/or the trajectory of the distal end DE of the guidecatheter 14 may be calibrated to an IGS system such as the InstaTrak®surgical image guidance system (available from GE Healthcare, Inc.,Schenectady, N.Y.) using a suitable calibration tool. FIGS. 4A-4C show acalibration tool 50 of the present invention which may be used for thispurpose. This calibration tool 50 comprises a rigid body having acatheter shaft receiving groove 51 which extends into a firstcalibration tip 52 on one side and a second calibration tip 54 on theother side. The shaft 16 of guide catheter 14 snap fits into the shaftreceiving groove 51 with its distal end DE positioned in secondcalibration tip 54. An important embodiment of the calibration toolinvention of the present application is the use of two calibration tips.The calibration tool in this important embodiment is constructed suchthat the axis that runs through the two calibration tips is coincidentwith the axis of the distal opening of the guide device. With thisconstruction when the image guidance system is calibrated to both tips,it is also calibrated to the trajectory extending out from the distalopening of the guide device. Therefore, it is also calibrated to theaxis along which a medical device would travel as it exits the distalend of the guide device which prospective trajectory can be displayed onthe monitor of the image guidance system. Thus a variety of calibrationtools 50 may be designed, each adapted to be used with a particularguide catheter 14 as a result the calibration tool may accommodate adevice with only one angle or it may a variety of angled devices. Iftrajectory is not desired, a calibration tool with only one calibrationtip can be used. Alternatively, the system can calibrate trajectoryusing a single tip calibration tool and a hole of known size andorientation in the headset attached to the patient. Calibration tool 50may also have one or more guide markings 56 indicating the type of guidecatheter 14 that can be used with that calibration tool 50. In apreferred embodiment, guide markings 56 are etched into calibration tool50.

In the particular embodiment shown in FIGS. 4A-4C, calibration tool 50is designed to accommodate either of two Relieva™ Sinus Guide Catheters(available from Acclarent, Inc., Menlo Park, Calif.) with curved distaltips curved at 70° and 110° respectively. In typical use with theInstaTrak® IGS system (available from GE Healthcare, Inc., Schenectady,N.Y.) the Relieva™ Sinus Guide Catheter is attached to the adapterdevice 10 as described above and as shown in FIG. 4C. The catheter shaft16 is snap fit into the catheter shaft receiving groove 51 such that thedistal end DE of the guide catheter shaft 16 is positioned within a tipreceiving recess in second calibration tip 54. An imageable headset isattached to the subject's body and an imaging scan is performed to imagethe headset along with the subject's body using a tomographic imagingmodality such as CT, MRI, etc. In a preferred embodiment, the headset isplaced on the bridge of the nose and on the external ear canals of thepatient. After the imaging scan is completed, the image data istransferred to the InstaTrak® IGS system. Thereafter, at the time of alater medical or surgical procedure, the guide catheter guide 14 andelement 12 are attached to the adapter device 10 as described above.Identifying magnets 44 are positioned in the appropriate magnet slots 42to type of guide catheter 14 being used. The shaft 16 of the guidecatheter 14 is snap fit within shaft receiving groove 52 such that thedistal end DE of the catheter shaft 16 is positioned within the tipreceiving recess of second calibration tip 54. The headset is placed onthe patient in the precise location as that used during the tomographicimaging scan. The electromagnetic transmitter 58 is attached to thepatient headset. The first calibration tip 52 is then inserted into atip receiving location, such as a well, cavity, notch or otherdepression 60 formed on the electromagnetic transmitter 58. Severalreadings may be taken using the IGS system with varying orientations ofguide catheter 14 while keeping first calibration tip 52 within thedepression 60 of the transmitter 58. Thereafter, the second calibrationtip 54 is fitted into depression 60 of transmitter 58 and several morereadings are taken using the IGS system with varying orientations ofguide catheter 14 while keeping second calibration tip 54 insidecalibration depression 60. In this way, the specific orientation of thecurve formed in the catheter shaft 16 is calibrated to the IGS system'scomputing device. Also, the position of the distal tip of guide device14 is located at a fixed offset with respect to the position of eithercalibration tip 52 or 54. The offset is used to calibrate the positionof the distal end DE of guide catheter 14 relative to theelectromagnetic IGS system. The offset may be programmed into the IGSsystem or may be manually entered by the IGS system via a user interfacesuch as a keyboard, keypad, touch screen, etc. The IGS system will beprogrammed to automatically calculate the position and/or theorientation of the distal end DE of the guide catheter 14.

After the calibration process is complete, the guide catheter 14 isremoved from the calibration tool 50 and the medical or surgicalprocedure is conducted.

It is to be understood that the particular design and construction ofthe adapter device 10 shown in FIGS. 1-4C is not limiting. Various othermodes of design and construction may be used within the scope of theinvention claimed herein. One of many such examples is shown in FIGS.5A-5C.

With reference to FIGS. 5A-5C, there is shown an alternative adapterdevice 10 a which comprises an adapter body 70 having a element holdingfixture 72 and a guide catheter holding fixture 74. In this example, theelement holding fixture 72 comprises element clamping members 24 asimilar to those of the embodiment shown in FIGS. 1-4C for clamping andholding the element 12 in substantially fixed position relative to theadapter device 10 a. Also in this example, the guide catheter holdingfixture 74 comprises a male Luer connector 76 and a catheter shaftsupport member 78. As seen in FIGS. 5B and 5C, the proximal portion PPof the guide catheter shaft 16 is inserted into the catheter shaftsupport fixture 78 and the male Luer connector 76 is connected to thefemale Luer connector hub 15 on the proximal end of the guide catheter14. This arrangement firmly holds the guide catheter 14 in substantiallyfixed position relative to the adapter device 10A. Optionally, aconstraining groove 80 may be formed in the adapter body 70 to receiveone of the opposing radial projections 40 on the proximal Luer hub 15 ofthe guide catheter 14, thereby defining and maintaining the rotationalorientation of the guide catheter 14 in the same manner as describedabove with respect to the other embodiment of the adapter device 10. Ina further embodiment, the guide catheter 14 can be fixed at anyrotational orientation the physician chooses by turning the guidecatheter to the desired orientation and then tightening and locking therotating Luer connector 76 to the proximal Luer hub 15 of the guidecatheter 14. In another embodiment, the proximal hub of the guidecatheter 14 can have a hexagonal shape or other shape that fits into amatching shaped opening in the adapter device.

The adapter devices of this invention, including the embodiments of thedevice 10, 10 a shown in these drawings, can be used as accessories tothe Relieva™ Sinus Guides (Acclarent, Inc., Menlo Park, Californa) andthe Instalrak™ 3500 Plus and ENTrak™ Plus IGS systems (GE Healthcare,Inc., Schenectady, N.Y.). The combination of the adapter device 10, 10 aand the Instalrak™ 3500 Plus or ENTrak™ Plus IGS system can be used toprovide image guidance capabilities to the Relieva™ Sinus Guide fornavigation in the paranasal sinus anatomy. This combination can be usedto track the distal end DE of the Relieva™ Sinus Guide and/or displayits trajectory on a monitor. Specific uses of the adapter device 10, 10a include image guided balloon dilation procedures as well as other ear,nose or throat procedures and procedures elsewhere in the body.

It is to be further appreciated that the invention has been describedhereabove with reference to certain examples or embodiments of theinvention but that various additions, deletions, alterations andmodifications may be made to those examples and embodiments withoutdeparting from the intended spirit and scope of the invention. Forexample, any element or attribute of one embodiment or example may beincorporated into or used with another embodiment or example, unless todo so would render the embodiment or example unsuitable for its intendeduse. All reasonable additions, deletions, modifications and alterationsare to be considered equivalents of the described examples andembodiments and are to be included within the scope of the followingclaims.

1-43. (canceled)
 44. An adapter device useable for attaching anelectromagnetic image guidance element to a medical device, a distalportion of said medical device being insertable into the body of a humanor animal subject during performance of the procedure and a proximalportion of said medical device remaining outside of the subject's bodyduring performance of that procedure, said adapter device comprising:(a) a body portion; (b) a medical device holding portion having alongitudinal axis, wherein the medical device holding portion isconfigured to firmly hold the proximal portion of the medical devicerelative to the longitudinal axis, wherein the medical device holdingportion defines a longitudinal plane which extends along thelongitudinal axis, wherein the medical device holding portion includes afixed channel member unitarily coupled to the body portion; and (c) anelement holding portion comprising: (i) a distal end, (ii) a proximalend, and (iii) an engagement element coupled to the body, wherein theengagement element is partially located between the distal end of theelement holding portion and the proximal end of the element holdingportion; wherein the engagement element is configured to directly holdthe image guidance element firmly in a substantially fixed spatialrelation to at least one location of the medical device while allowing aportion of the medical device to be inserted into the subject's body forpurposes of the procedure.
 45. A device according to claim 44 whereinthe medical device holding portion comprises a clamping apparatus thatengages the proximal portion of the medical device.
 46. A deviceaccording to claim 45 wherein the clamping apparatus that engages theproximal portion of the medical device comprises a channel through whichan elongate medical device may be inserted and apparatus for tighteningabout the medical device within said channel such that the medicaldevice is held in a fixed position relative to said adapter device. 47.A device according to claim 46 wherein the clamping apparatus comprisesfirst and second clamping components between which the proximal portionof the medical device is positionable and the tightening apparatus isuseable to cause the first and second clamping components to tightenupon and hold the proximal portion of the medical device therebetween.48. A device according to claim 44 wherein the medical device holdingportion comprises a connector configured to mate with a connector on theproximal end of the medical device.
 49. A device according to claim 48wherein the connector of the medical device holding portion comprises amale Luer connector.
 50. A device according to claim 49, furthercomprising a medical device, wherein the medical device has a proximalend, wherein the proximal end of the medical device has a connector,wherein the medical device holding portion further comprises a supportmember that supports the medical device at a location distal to theconnector on the proximal end of the medical device.
 51. A deviceaccording to claim 50 wherein the support member comprises a grippingportion which grips the medical device at a location distal to theconnector on the proximal end of the medical device.
 52. A deviceaccording to claim 51 wherein the gripping portion is designed such thatthe medical device will snap fit therein.
 53. A device according toclaim 44 wherein the medical device holding portion also prevents themedical device from undergoing substantial rotation.
 54. A deviceaccording to claim 44 wherein the medical device holding portion hasradial apertures, wherein the radial apertures are configured to receiveradial projections on the medical device, wherein the radial aperturesare configured to prevent the medical device from undergoing substantialrotation.
 55. A device according to claim 44 further comprising indiciaindicating information about the type of adapter device being used orthe type of medical device that the medical device holding portion isconfigured to receive, the indicia being readable by an image guidancesystem when the image guidance element is positioned in the elementholding portion.
 56. A device according to claim 55 wherein said indiciacomprise magnets that produce a magnetic field which identifies thespatial relationship that will exist between sensor(s) of the imageguidance element positioned in the element holding portion and aselected location on a medical device to which the adapter device isattached by way of the medical device holding portion.
 57. A deviceaccording to claim 44 wherein the engagement element of the elementholding portion is distal in relation to the medical device holdingportion.
 58. A device according to claim 44 wherein the medical deviceholding portion and the element holding portion are designed to hold themedical device at an angle relative to the element.
 61. A systemcomprising an adapter device according to claim 44 further incombination with an image guidance element that may be attached to theadapter device by way of the element holding portion.
 60. A systemcomprising an adapter device according to claim 44 further incombination with a medical device which may be attached to the adapterdevice by way of the medical device holding portion.
 62. A systemcomprising an adapter device according to claim 44 further incombination with a) a medical device that may be attached to the adapterdevice by way of the medical device holding portion and b) an imageguidance element that may be attached to the adapter device by way ofthe element holding portion.
 63. A system according to claim 62 whereinthe medical device has a trackable location on the portion of themedical device that is inserted into the subject's body and wherein theadapter device further comprises indicia that indicates the spatialposition of the trackable location relative to one or more sensor(s)incorporated in the element.
 64. A system according to claim 61 whereinthe medical device is a guide catheter.
 65. A system according to claim61 wherein the medical device is a stiff member having a dilatationballoon at the distal portion.
 66. A system for guiding the advancementof a device within the body of a patient comprising: (a) a guidestructure dimensioned to allow advancement of the device into the body,the guide structure comprising a distal exit portion oriented to anangle between zero and 180 degrees relative to an axis of the guidestructure and a proximal portion having a radially nonuniform featureoriented in a fixed relationship with respect to the angle of distalexit portion; (b) an adapter device capable of releasably attaching tothe guide structure, wherein the adapter device comprises an engagementelement, wherein the engagement element defines an aperture; (c) anavigation element confined within the engagement element of the adapterdevice, wherein the navigation element is capable of being detected by acomputer-based navigation system, the navigation element housed withinthe aperture of the engagement element during use; and (d) a medicaldevice positioned in the guide structure and advanceable along the guidestructure.
 67. A system according to claim 66 wherein the angle is inthe range of about 0 to about 45 degrees.
 68. A system according toclaim 66 wherein the angle is about 20 degrees.
 69. A system accordingto claim 66 further comprising an endoscope useable to visualize thepositioning of at least one portion of the medical device within thepatient's body.
 70. A system according to claim 66 further comprising afluoroscope useable to identify the position of at least one portion ofthe medical device within the patient's body.
 71. A system according toclaim 66 wherein the engagement element comprises a clamp.
 72. A guidesystem comprising: (a) an adapter body, wherein the adapter body furtherdefines a guide catheter channel, wherein the guide catheter channelextends through the adapter body in a radially non-uniform mannerwherein the adapter body comprises an engagement element, wherein theengagement element defines an aperture; (b) an image guidance elementoperably configured for detection by a computer-based navigation system,wherein the engagement element is configured to receive the imageguidance element; and (c) a medical device configured to fit in theguide catheter channel and be advanced along the guide catheter channel.